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I got a new job..

I have always wanted to work in Commercial Heating and Air Conditioning and refrigeration, I now have finally landed a job in that area (no more crawl spaces for me). What I did not realize was the world of hurt I was putting myself in.

Bigger / more controls, bigger / more boards, bigger and more compressors, bigger and more contactors, more power, robbing t stats, make up air, vents, and the list goes on.

I was not aware how big the difference is between commercial and residential work was, but I do like it more ( no crawl spaces).

My new boss is well respected by his employees and has treated me great, not sure how many employees there is in all, but I have met 5 of them, and the shortest term employee is 15 years. My boss hired two new guys, me and this other guy that just got past his 90 days who I just met the other day.

I am very excited to have landed this job with this company, and hope to grow with them for years to come (I see great long term potential, and lots of growth with opportunity this company).

I have a few questions here.

Do you guys have any tricks that you have come up with to help make working on these units easier?

I keep getting told to treat each unit as one unit, just like in residential. Told to just break it in to each individual units, but that is hard to do when everything is all tied together, and the wires are all over the place, and you got a few boards, more controls, 3 compressors in one unit.

I am working on package units, not one brand, all different brands. I went to school, and worked in residential for a while, and was going out on my own in residential, now that I am in Commercial I am still out on my own, but lots of times find myself calling people for support, where as before I did not do that, well not as much.

I have no problems reading. I still have my school books next to me, I am even thinking of keeping it in my truck.

Originally Posted by Workin4TheMan

The best way to troubleshoot any machine is to first learn it's "Sequence of Operation" once you know that, when things aren't working you have an idea where to start.

And being able to follow a wiring diagram is critical.

Remember we all started knowing nothing

I understand the Sequence of Operation in residential work well, and follow a residential wiring diagram, it's a little easier, so if something is wrong it's easy to spot.

Most of the time in commercial I have found it's not as easy to follow, nor is it as easy to spot the problem.

I appreciate the nice comment about we all start knowing nothing, that is why I turned here, I wanted to find out how others learned this side of things.

how about his one...with cool mornings comin around with the first day of fall here,the call will be the unit runs in the "cool" morning but shuts down in the "warmer" afternoons and control power is lost within the rooftop....situatuin fix supply fan runs fine to do econo cooling then the afternoon sun swings and a call for DX happens bad condenser fan motor blows the fuses and with that the primary to the control TR is lost..sen guys walk in with one of those boat anchor big Trane rooftop TRs i found the problem.quick fix to gie them cooling swing the TR primary over to the compressor contact L side or the block...go get a motor

how about his one...with cool mornings comin around with the first day of fall here,the call will be the unit runs in the "cool" morning but shuts down in the "warmer" afternoons and control power is lost within the rooftop....situatuin fix supply fan runs fine to do econo cooling then the afternoon sun swings and a call for DX happens bad condenser fan motor blows the fuses and with that the primary to the control TR is lost..sen guys walk in with one of those boat anchor big Trane rooftop TRs i found the problem.quick fix to gie them cooling swing the TR primary over to the compressor contact L side or the block...go get a motor

Don't worry, I speak Max lol

What he is saying is he has gotten service calls on large Trane Intellipaks where they would cool fine in the mornings using an outside air economizer, and then when the sun comes up and the heat hits in late-morning to early-afternoon, the unit calls for DX compressor cooling. Because of the way the older style Intellipaks were wired, a bad condenser fan motor that shorted to ground and blew the fuses would cause the control power transformer primary side power to be lost, along with communication to the unit. Some people would mis-diagnose this as a bad transformer and confidently walk into the parts-house looking for a new transformer. This resulted in much laughter and ridicule of said technician. The right thing to do is to move the wires that go to the primary side of the transformer to a line voltage terminal block to get the unit operational while you go to pick up a new fan motor.

Good job, and good luck!!! Commercial HVAC is a field that'll definitely keep your brain engaged! If you're on this site to begin with, you're probably someone who is committed to being a student of the trade and understanding this stuff on a level that most don't care to.

First and foremost, you need to understand how to work on this big stuff safely without getting yourself killed by the multitude of moving parts, high temperatures, and high voltages. You need to have an understanding of electricity, motors, and motor controls that far surpasses what most electricians know. You're still working with a vapor-compression refrigeration cycle; the fundamentals are not much different from what you're used to working with.

When you run into a system that you don't understand or haven't seen before, try to find some literature on it and spend a few minutes reading when you're in your van eating your lunch or whatever. DO NOT be too proud to pick up the phone and ask your co-workers questions or find the tech support numbers for each manufacturer. Most people are eager to help you if they see that you're not just being lazy and looking for the answer without working for it. When you're troubleshooting something, gather info and readings in a methodical way, jot them down on a pad, and try to look at the big picture. Troubleshooting is a process of elimination. Start with the simple, cheap stuff, and work your way up to the complex, spendy stuff until you find the problem.

The commercial field can be very rewarding to work in, professionally and financially. Best of luck to you.